condition mean min max ZT0-3 11.311203 11.311203 11.311203 ZT4-7 9.55799 9.55799 9.55799 ZT8-11 8.669439 8.669439 8.669439 ZT12-15 8.589763000000001 8.589763000000001 8.589763000000001 ZT16-19 8.276771 8.276771 8.276771 ZT20-23 8.675132 8.675132 8.675132